forked from OSchip/llvm-project
106 lines
3.7 KiB
C++
106 lines
3.7 KiB
C++
//===--- CGException.cpp - Emit LLVM Code for C++ exceptions --------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This contains code dealing with C++ exception related code generation.
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//
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//===----------------------------------------------------------------------===//
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#include "CodeGenFunction.h"
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using namespace clang;
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using namespace CodeGen;
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static llvm::Constant *getAllocateExceptionFn(CodeGenFunction &CGF) {
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// void *__cxa_allocate_exception(size_t thrown_size);
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const llvm::Type *SizeTy = CGF.ConvertType(CGF.getContext().getSizeType());
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std::vector<const llvm::Type*> Args(1, SizeTy);
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const llvm::FunctionType *FTy =
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llvm::FunctionType::get(llvm::Type::getInt8PtrTy(CGF.getLLVMContext()),
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Args, false);
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return CGF.CGM.CreateRuntimeFunction(FTy, "__cxa_allocate_exception");
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}
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static llvm::Constant *getThrowFn(CodeGenFunction &CGF) {
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// void __cxa_throw (void *thrown_exception, std::type_info *tinfo,
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// void (*dest) (void *) );
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const llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(CGF.getLLVMContext());
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std::vector<const llvm::Type*> Args(3, Int8PtrTy);
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const llvm::FunctionType *FTy =
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llvm::FunctionType::get(llvm::Type::getVoidTy(CGF.getLLVMContext()),
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Args, false);
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return CGF.CGM.CreateRuntimeFunction(FTy, "__cxa_throw");
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}
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void CodeGenFunction::EmitCXXThrowExpr(const CXXThrowExpr *E) {
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// FIXME: Handle rethrows.
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if (!E->getSubExpr()) {
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ErrorUnsupported(E, "rethrow expression");
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return;
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}
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QualType ThrowType = E->getSubExpr()->getType();
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// FIXME: We only handle non-class types for now.
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if (ThrowType->isRecordType()) {
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ErrorUnsupported(E, "throw expression");
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return;
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}
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// FIXME: Handle cleanup.
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if (!CleanupEntries.empty()){
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ErrorUnsupported(E, "throw expression");
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return;
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}
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// Now allocate the exception object.
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const llvm::Type *SizeTy = ConvertType(getContext().getSizeType());
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uint64_t TypeSize = getContext().getTypeSize(ThrowType) / 8;
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llvm::Constant *AllocExceptionFn = getAllocateExceptionFn(*this);
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llvm::Value *ExceptionPtr =
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Builder.CreateCall(AllocExceptionFn,
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llvm::ConstantInt::get(SizeTy, TypeSize),
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"exception");
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// Store the throw exception in the exception object.
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if (!hasAggregateLLVMType(ThrowType)) {
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llvm::Value *Value = EmitScalarExpr(E->getSubExpr());
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const llvm::Type *ValuePtrTy = Value->getType()->getPointerTo(0);
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Builder.CreateStore(Value, Builder.CreateBitCast(ExceptionPtr, ValuePtrTy));
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} else {
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// FIXME: Handle complex and aggregate expressions.
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ErrorUnsupported(E, "throw expression");
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}
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// Now throw the exception.
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const llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(getLLVMContext());
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llvm::SmallString<256> OutName;
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llvm::raw_svector_ostream Out(OutName);
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mangleCXXRtti(CGM.getMangleContext(), ThrowType, Out);
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// FIXME: Is it OK to use CreateRuntimeVariable for this?
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llvm::Constant *TypeInfo =
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CGM.CreateRuntimeVariable(llvm::Type::getInt8Ty(getLLVMContext()),
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OutName.c_str());
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llvm::Constant *Dtor = llvm::Constant::getNullValue(Int8PtrTy);
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llvm::CallInst *ThrowCall =
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Builder.CreateCall3(getThrowFn(*this), ExceptionPtr, TypeInfo, Dtor);
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ThrowCall->setDoesNotReturn();
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Builder.CreateUnreachable();
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// Clear the insertion point to indicate we are in unreachable code.
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Builder.ClearInsertionPoint();
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}
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